Someone is going to answer "get a cat." Ignore that answer. In fact, give me just a moment:
TO ANYONE ANSWERING "GET A CAT:" Stop giving that stupid answer. It is a useless response. Here's why:
1) OP cannot have or does not want a cat
2) OP already has a cat and it's not working
3) that's enough reasons. Telling someone to take on a 10-20 year commitment to a pet just to get rid of some mice is stupid. Stop doing that.
Okay, to business.
Peppermint oil is indeed effective, but its range is very limited and it only lasts for a couple of days. Mice will avoid the immediate area of the oil - they won't walk right through it, for example - but it doesn't project a magical force field that automatically ejects all mice from your home. Shawn Woods proved this on his YouTube channel, "Mousetrap Monday."
Keep it up with the traps. Place traps against the wall, with the business end next to the wall. It gives the mouse fewer directions to jump, makes them less able to get away when the trap pops.
if your traps aren't hitting, change bait. I use chunky peanut butter and I smear it on the UNDERSIDE of the bait pedal. That way the mouse has to wiggle and jostle the trigger to get to the peanut butter *BANG*
Place more and more traps. They're cheap.
NEVER use poison. The mouse might die anywhere and you're stuck with the stink until it dries up.
Go around your whole place, move furniture away from walls, stoves and fridges and whatnot. Find every tiny crack and crevice. Wad up some stainless-steel scouring pad into the hole, then caulk the mesh in place. They won't chew through that anytime soon.
Make sure you aren't leaving garbage in the bin under the sink overnight, or water standing out where they can get to it, or fresh veggies arranged attractively in a bowl. Seal up everything in chew-proof containers so their only food source is the bait on the traps.
Good luck with it.